In shooting ranges, shooters may wish to fire at a target that is located a set distance away from the shooter. Range distance markings are often supplied, so that a shooter can practice firing at a target located (for example) exactly 10, 20, or 30 yards away, as desired. In some scenarios, a shooter may practice firing at a rapidly-approaching target, simulating an attack, while other scenarios include the target moving laterally across the shooter's field of vision. In other training exercises, the target may be moved forwards or backwards at different speeds, simulating an advance or retreat. In other applications, a shooter may wish to bring the target carrier to within arm's length, in order to remove a badly-perforated paper target and attach a fresh one in its place, or to measure the distance between shots in a grouping.
Because walking downrange in order to adjust target placement or movement is extremely dangerous, a number of means of mechanically moving a target in a linear fashion, towards and away from a shooter or laterally across the shooter's field of vision, have been developed. Most indoor shooting ranges today use a moveable target track, located above each lane of the range. Outdoor ranges often employ targets that move from side to side, or down a long track—in such cases, the target-moving mechanisms are often located behind a concrete or other bullet-proof, low wall, while the target itself can be seen over the wall. When a shooter wishes to move the target, he or she can press a toggle connected to at least one motor.
When activated, the motor typically pulls on the appropriate side of a doubled cable, thus moving a target carrier releasably attached to that cable in a direction relative to the shooter. The motor may either be mounted at one (or both) ends of the lane or outdoor track, or may be within the target carrier itself. Although target carriers which do not employ cables exist, such devices may be slower than cable-driven ones, and often contain more electronic and mechanical parts which must be serviced to prevent electrical arcing between brushes and conductor strips.
Target holders attached to the target carrier are typically capable of holding a variety of different types and sizes of target, including paper, cardboard and steel targets, as well as longer or shorter targets for kneeling or standing shooters, bull's eye round targets, or silhouette targets. Targets may be attached with clips, clamps, screws, and the like, and may themselves be pivotable or stationary relative to the target carrier.
As the ability to provide a movable (or moving) target is highly desirable, such trolleys or carriages often see a great deal of use, and thus range owners prefer lightweight systems which require less power to run and which may place less strain on ceiling supports. But because bullets may ricochet from other parts of the range and strike the target carrier or cable, the entire system must be very robust. It is beneficial if the target carrier has some degree of suspension—that is, it starts and stops smoothly when the motor is engaged. Further, servicing a target carrier—especially one stuck in the middle of the range—can typically only be done after closing or when the rest of the range is shut down, due to the danger of entering a range while shooters are active, so it is beneficial if the target carrier requires very little servicing.
One of the major reasons that a target carrier must be serviced is poor cable tension. Target retrievers should generally be kept at a tautness of between about 20 and 80 lbs, as required by the particular range and the targets being moved. When cables are loose, the movement of the target may become particularly jerky and hard to control with any level of precision. Moreover, loose cables may cause target carriers to jump their tracks entirely, or slip from the motor pulleys. The cable may become tangled or looped around objects, or may rub against rough surfaces thus causing wear on either the cable or the surface. Cables may stretch over time, and keeping cables tight enough is an ongoing concern. Cables which are too tight, however, put unwanted strain on motors, target carriers, and other parts.
Another difficulty in adjusting cable tension is that target carriers or portions of target carriers must typically be removed from the cable before the cable can be adjusted. This can be an involved process best done by trained maintenance personnel.
One such means of addressing these problems is U.S. Pat. No. 3,614,102 to J. Nikoden, Sr. A first cable has one end spooled clockwise on a rotatable take-up drum which moves laterally about its central axis on a threaded shaft as the drum rotates. The opposite end of the cable is connected to a target carrier, providing motive force in one direction along a track and one conductor for power at the carrier. A second cable has one end spooled counterclockwise on the rotatable take-up drum and the opposite end connected to the target carrier, thus providing motive force in a direction opposite that provided by the first cable. The pitch of the threads on the shaft is equal to the diameter of the cables. One of the cables wraps around an idler pulley at the end of the track opposite the take-up spool mechanism. Such a design is rather complex, requires frequent lubrication of the threaded shaft, and has no means of quickly determining cable tension providing suspension.
Still another design used to provide linear movement to a carrier utilizes a target carriage which is pulled along the track by a steel puller cable, takeup pulley, and drive motor arrangement. Such a target system design is depicted in U.S. Pat. No. 4,889,346 to Donald M. Destry, et al.
While such devices are functional, there is a need for a simple, reliable, and robust new system for providing linear movement to a track-mounted carrier, while providing both suspension and easy means of adjusting cable tension.
The various embodiments described by the present specification are described in greater detail below.